<p>Three index organizations are introduced for use in the evaluation of a query in an object-oriented or nested relational database. Detailed models of the three indexes are developed. Using the models, the storage cost, retrieval cost, and update cost of these indexes are evaluated, and a number of observations are made about the use of these indexes for evaluating queries for object-oriented or nested relational databases. A comparison of the combined retrieval and update costs for the three indexes is also included. It is shown that the degree of reference sharing among objects for the various classes in the path influences both the retrieval and update costs.</p>